Questions tagged [filter-bank]

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Advantages of an orthogonal filterbank

What are the advantages orthogonal filterbanks such as the DFT or DCT have over non-orthogonal filterbanks? I have heard quite often that they have attributes that are desirable when modifying the ...
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15 views

Bank Filter over a 1D signal

I would like to apply a filter bank decomposition over a time series signal. If I am correct, it is necessary to take a low pass and a high pass filter, and then convolve them with the time series. ...
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46 views

Understanding the magnitude of frequency response filterbank based on elliptic filters

I've implemented a 10-channels filterbank with octave-scaled second-order elliptic filters using the Python's library scipy.signal. Here is the magnitude of the frequency response: Can someone ...
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54 views

Why do additional harmonics arise after the filter bank?

I'm trying to implement direct implementation of MDCT filter bank. So, some additional artefacts have appeared after all of the routines. The spectrum of the initial signal looks like: ...
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1answer
115 views

Discrete Wavelet Transform (DWT) Filter Bank

I have some stumbling block in my thesis writing. Do we use the same filter pair while implementing DWT filter bank with downsampling of the filter output, or filters do change also from level to ...
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21 views

Is the convolution between a decomposition and reconstruction filter a scalar?

I'm very new in a research topic about wavelet filtering and I received an observation by a professor, but I actually cannot understand it, so I ask you to help me. Suppose to perform a stationary ...
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26 views

Seperation of multi-carrier signal using Square Root Nyquist filter

My goal is to separate multi-carrier to single carrier outputs. I intend to do it using Polyphase FBMC. Each of my carrier is 10 MHz in bandwidth. I have 256 such carrier in the channel. Thus I ...
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16 views

Equal power filterbank

Is there a specific algorithm/formula for computing the bandwidths of filter banks across a frequency range where each bank has equal power/volume/intensity? (The bandwidths will be different for ...
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13 views

Continuous Wavelet Filter Bank Frequencies

I have followed instructions on how to create a single Morlet wavelet, and can change the centre frequency of the wavelet. My question now, is I would very much like to create a filter bank. How do ...
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2answers
108 views

Polyphase Analysis Filter Bank

I have a question regarding the polyphase DFT filter bank implementation in this page. (https://cnx.org/contents/Peqc-TK2@16/Uniformally-Modulated-DFT-Filterbank) In figure 2, to analyze the kth ...
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32 views

Noising audio in MFCC space

I am training up an audio recognition neural network using MFCCs. Its been shown to be very beneficial to artifically add noising and reverb of the original audio when training a neural network (Data ...
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78 views

Discrete Wavelet Transform: Specifics of Filter Bank

So I have been given to understand that the discrete wavelet transform is able to provide both time and frequency resolution in ways that classic Fourier and even short time Fourier cannot. By ...
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1answer
51 views

How are 12 outputs being reconciled so that a Homomorphic filter could be applied?

Take a look at this paper. It writes in the section 4.1: We selected 12 not overlapping filters, to analyze 12 different directions, rotated with respect to 15° each other. A homomorphic filter is ...
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2answers
705 views

What is a filter bank?

Suppose, I have 3 kernels: $$ \left[ \begin{array}{cc} a&b&c\\ d&e&f\\ g&h&i \end{array} \right] $$ $$ \left[ \begin{array}{cc} p&q&r\\ s&t&u\\ v&...
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98 views

How does this Odd stacking DFT work?

I have just read on page 3 of this paper: https://www.onsemi.com/site/pdf/Filtering_Hearing_Ai.pdf That an "odd stacking" DFT can be created, essentially sacrificing the DC and Nyquist bands to ...
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1answer
42 views

Speech Processing applications: stereo data for features

I am working on speech databases that have a stereo format. I want to extract spectral information (Mel-filterbanks, MFCC, LPCC) and also some other prosody features like the fundamental Frequency F0. ...
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1answer
117 views

Wavelets and bank filters

The wavelet transform has a problem as it gives poor time resolution for low frequencies and poor frequency resolution for high frequencies according to uncertainty conditions. This appears well ...
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0answers
123 views

Perfect reconstruction of 2 channel filter bank

I am studying Perfect reconstruction of 2 channel filter bank for using Biorthogonal Spline wavelet for decomposing ECG signal. I am using Wavelets and Filter Banks By Gilbert Strang, Truong Nguyen to ...
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1answer
112 views

Filter bank for complex spectrum

I'm using a complex-valued baseband signal as my input for subband adaptive filtering. Therefore i have a complex input spectrum. My problem is now, how to split my complex spectrum into $N$ equally ...
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1answer
256 views

Norm MPEG-1 Layer III (Mp3) Filter banks distortion

So, I'm working with the filter banks used in Mp3, in Matlab. I am obtaining quite a huge distortion in the output and I don't really know whether I'm making something wrong. I've reviewed the ...
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0answers
142 views

Converting a parallel filterbank to cascade structure

I have a bank of 12 bandpass filters (biquads) that I use for spectral modelling. Each filter is centered around a specific "mode" frequency, and has its own resonance. Until now I have implemeted ...
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2answers
132 views

Sub-band partitioning of filter-banks

In ECE-700 Filterbank Notes the partitioning is $ \Delta = \frac{2\pi}{M}$ with center-frequencies at $ \omega_k = \frac{2\pi}{M}k$ which makes me wonder, considering that frequencies in the range ...
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3answers
558 views

What is the relation between windowing and hopping in audio DSP

While using short-time Fourier transform (STFT), it is common to use window function, usually tapered. Will this not alter the original signal $x[n]$ and the STFT may no more be the true STFT of $x[...
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169 views

What is advantage of Logarithmic Sampling?

Logarithmic Fourier Transformation This paper starts off in the abstract saying that the given audio signal is sampled logarithmically. We also know that the human ear has a sort of a filter bank ...
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0answers
154 views

What is logarithmic mapping in a filter bank such as the one in the human ear?

"The spacing of the filters in a filter bank used to make an ordinary spectrogram is linear, whereas an auditory filter bank has a spacing that corresponds to the way in which sinusoidal frequency ...
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1answer
39 views

Sub-band factor 0.5 in uniform filterbank

Is there someone who knows where the factor $\frac{1}{2}$ in front of $U_i(z)$ comes from?
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1answer
35 views

Should I (and if yes, how can I) assure channel-dependant temporal accuracy in a filterbank?

Imagine a filterbank with N channels. A possible implementation is a sliding short-time FFT. If you want to capture frequencies as low as 100 Hz, the length of your sliding window should be at least ...
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2answers
223 views

Is this signal perfect reconstructable?

The question is as follow: Let me do the analysis: The downroad first: \begin{align} X_1(z) &= z^{-1}X(z)\\ X_2(z) &= \frac{1}{2}\left\{X_1\left(z^\frac{1}{2}\right)+X_1\left(-z^\frac{1}{2}\...
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3answers
886 views

MP3 Filterbank + MDCT: Why?

What is the rationale for the two-step process the MP3 format performs, first decomposing the input into 32 subbands of 6/18 samples each then performing MDCT on each subband individually? Why not ...
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1answer
544 views

How to reverse Mel scale

The conventional MEL scale converts the frequency scale using the following formula: $$M_f = 1127.01048 \cdot \log\left(\frac{f}{700} +1\right)$$ I want to use a reverse scale where resolution is ...
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1answer
280 views

Difference(relation?) between filter banks and wavelet decomposition

I'm implementing multirate system and met concepts of filter banks and polyphase decomposition of filters. While trying to understand them, I've found that they look very similar to wavelet ...
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1answer
440 views

Frequency Response FIR Filter Bank

I want to determine the frequency response of a filter bank from the input x[n] to the four output channels. $H_0$ is an lowpass and $H_1$ is a highpass filter. Both are FIR filters and I have the ...
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2answers
471 views

Is subtraction a common method for efficient filtering?

I've recently been doing some DSP programming with regard to filter banks. One topic that I've come across was that of the dyadic filter bank. This filter bank essentially breaks a signal into sub-...
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1answer
263 views

Use polyphase representation to construct a perfect reconstruction filter bank

I'm posting this question in response to Question about zero-phase filter bank This is a homework question for which I found an answer, but I didn't do it the way I was supposed to. I'm wondering ...
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2answers
303 views

Question about zero-phase filter bank

I found what I believe is a valid solution to the following assignment problem but the answer is bothering me. Let $$H_0(z) = 1+2z^{-1}+3z^{-2}+2z^{-3}+z^{-4}\quad\textrm{and}\quad H_1(z)=H_0(-z).$$...
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0answers
116 views

Are wavelets for audio spectrograms available as a simple FIR filter?

I have read that "Debauchies Wavelet is simply a short FIR" so i am searching for a single FIR that i can make into a filterbank, a precise "bandpass filter" that detects narrow frequencies, i.e. 1Hz ...
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2answers
368 views

Synthesis DFT Filter Bank

I have a DFT bank analyzer with N channels, but the the bandwidth of the signal occupies only the first 2 channels, therefore I'll reconstruct only these and not entire full bandwidth. I'd like to ...
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1answer
628 views

Oversampled polyphase filter banks

i would a confirm of this: with polyphase structure is possible only design a filter bank with a INTEGER oversampling ratio? For non-integer i've seen the weighted overlap-add metod, is right? thanks ...
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1answer
426 views

DFT Filter Banks

i have a doubt about DFT filter banks. For example I have $M=4$ channels and a filter with cut-off frequency of $0.25$ right. The prototype filter $H_0$ is a low-pass centered around $0$ ok. The ...
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3answers
146 views

Using FFT as a channeliser

This article mentions that the DFT/FFT can be used as a channeliser in a similar way to a filterbank. I get how the DFT filters into spectral bins, but its output is in the frequency domain, i.e. ...
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2answers
4k views

Purpose of using polyphase filter bank (PFB)

What is the advantage of using a polyphase filter bank (PFB) for spectral analysis over just using the FFT? In the standard "critically sampled" uniform DFT filterbank, the polyphase decimation/...
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1answer
144 views

“Undersampled” Polyphase Filter Bank

I'm working on an application where I want to grab high-resolution pieces of the spectrum, but I don't need the whole spectrum-- just a few bands. I've looked into using the Goertzel algorithm (too ...
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0answers
100 views

How many different filters are needed for in an iterated filter bank?

I'm trying to implement an iterated filter bank as described in the Subband coding chapter of the Really Friendly Guide to Wavelets. However, the text seems to suggest that The advantage of this ...
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0answers
827 views

Weighted overlap Add query

Weighed overlap add Filterbank structure is often used in speech coding. (https://www.onsemi.com/site/pdf/Filtering_Hearing_Ai.pdf) I have basic question with respect to analysis. what is the ...
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1k views

Design Filter Banks for every 100 Hz

I need to study a wave file for every 100 Hz. However, I dont know how can I design filer for each 100 Hz. Let's say 0-100 Hz, 100-200 Hz, ... , ((fs/2)-100) _ (fs/2) Hz. Is it any MATLAB code for ...
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75 views

How can I apply a Gabor filter to a sine waveform?

I am an ECE student, and I am doing my project on underwater communication. The main concept of my project is to denoise the signal by using UFB and WPD algorithms, and giving that output to a ...
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0answers
140 views

Optimal filter bank from SVD/PCA

Given a million data points in say 100d, is there a way to generate an optimal filter bank of say 20 filters from an SVD of the data ? Call the 100d space $F$ (as in Frequency), with coordinates $[f_1,...
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1answer
791 views

What are the main advantages and disadvantages of the lifting scheme?

Can anybody tell me the advantages of the lifting scheme and why it is better then a normal filter bank?
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2answers
416 views

Can anyone explain me this MDFT polyphase filter bank?

I found a very interesting piece of code for MDFT polyphase filter bank here. Unfortunately, there doesn't seem to be a paper describing the theory. Does anyone know some reference for the code? I'm ...
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1answer
2k views

Converting mel spectrogram to spectrogram

I have a set of songs for which I extracted the STFT (Short-Time Fourier Transform) and used the magnitude spectrum $|S|$ to calculate the mel spectrogram by using a mel filterbank matrix $M$, so $X=\...